Beloved, let us love one another, for love is from God, and whoever loves has been born of God and knows God. Anyone who does not love does not know God, because God is love.
Aside from it being metaphysically true (see here , here, and here), another reason to accept divine simplicity is because, as Scripture says, God *is* love. Not that God is capable of loving; has love as some dormant capacity, or whatever. No, the claim is stronger than that: God is… love.
This fits incredibly well with divine simplicity, which holds that whatever is in God, is God. Thus, whatever’s God’s power is just is whatever God’s love is. Notice, not that power (in us) is not the same as love (in us); here, we keep in mind the critically important principle of analogy. There is something like power in God, and whatever the ontological basis of that is, would be the same as whatever the ontological basis for there being something like love in God. Stretch concepts, as Fr. Norris Clarke called them. We cannot do metaphysics without them.